Not 100 % genuine slides, took from a couple of sources --> credits to those sources.
#important thing is students are able to learn conveniently
BIOLOGY GCE O level Syllabus
NOTE: NEED TO DOWNLOAD BECAUSE THERE ARE MANY MANY ANIMATIONS THAT HIDE SOME OF THE CONTENT
3. Unicellular organism
No part of the cell is far
from the external
environment
EASY O2 + nutrients
can go into the cell easily
Multicellular organism
Many cells are far from
the outside environment!
HARD diffusion alone
is not enough to bring
materials into these cells
UNICELLULAR VS MULTICELLULAR
THAT IS WHY WE NEED A
TRASNPORT SYSTEM!!
4. In humans,
Circulatory system transports blood to and from all parts of the
body.
Thus it functionally connects the aqueous environment of all
body cells to organs specialized for exchanging gases,
absorbing nutrients and disposing waste.
CIRCULATORY SYSTEM
1. It carries oxygen and food
to all cells in the body
2. It carries waste away from the
cells of the body
6. The human circulatory system consists of three
parts:
THE HUMAN CIRCULATORY SYSTEM
Heart
An organ that
pumps blood
around the
body
Blood vessels
A network of
tubes
To carry blood
around the
body
Blood
A liquid that
transports
materials
Arteries Capillaries Veins
7. Humans Closed circulatory system
Direction of blood flow:
HUMAN CIRCULATORY SYSTEM
Heart
Arteries Capillaries Veins
Pumps
blood
to
Back to
Backflow does
Not happen VALVES
10. Arteries receive blood directly from heart
Narrow lumen
Flow of blood fast + at high pressure
Thus, The walls of the arteries are THICK, MUSCULAR and
ELASTIC to withstand the pressure.
- Elastic enables arteries to stretch and recoil, which pushes
blood in spurts and gives rise to pulse
- Blood moves along the arteries by contraction and relaxation
of muscles in the walls.
Arteries branch into smaller vessels arterioles
(smallest), which connects to the smallest blood
vessel, capillaries
ARTERIES
11. Veins carry blood towards the heart
Blood pressure is lower than in arteries
Blood flows more slowly and smoothly Thin layer of wall and
elastic tissue
Have internal valves
Waste products are brought back to the heart when capillaries
join to form VENULES
VEINS
13. The CAPILLARY
Capillaries link Arteries with Veins
the wall of a capillary
is only one cell thick
they exchange materials between
the blood and other body cells.
The exchange of materials between the
blood and the body can only occur
through capillaries.
14. CHARACTERISTIC
S
ARTERIES VEINS CAPILLARIES
Direction of blood
flow
Carries blood from
heart organs
Carries blood
from organs
blood
Carries blood from
arterioles venules
Valves Absent except in
pulmonary artery
Present Absent
Size of wall Thick Thin A single layer of cells
Layer of elastic
and muscle tissue
Thick Thin Absent
Oxygen content Oxygenated except
pulmonary artery
Deoxygenated
except
pulmonary vein
Oxygenated arteriole
Deoxygenated venule
Color Red Bluish-red Bluish-red
Location Deep in muscle Nearer to body
surface
Inside all tissues
19. air sac in
the lung
oxygen
1 as blood flows through
the lungs the haemoglobin
in the red cells picks up
oxygen
20. air sac in
the lung
oxygen
1 as blood flows through the
lungs the haemoglobin in the
red cells picks up oxygen
2 Haemoglobin and
oxygen join to make
oxyhaemoglobin
21. air sac in
the lung
oxygen
1 as blood flows through the
lungs the haemoglobin in the
red cells picks up oxygen
2 Haemoglobin and
oxygen join to make
oxyhaemoglobin
3 when the blood flows
past cells with very little
oxygen in them the
oxyhaemoglobin breaks
down
22. air sac in
the lung
oxygen
1 as blood flows through the
lungs the haemoglobin in the
red cells picks up oxygen
2 Haemoglobin and
oxygen join to make
oxyhaemoglobin
3 when the blood flows past
cells with very little oxygen
in them the oxyhaemoglobin
breaks down
oxygen diffuses into the cells of the
body
oxygen is used for respiration
23. air sac in
the lung
oxygen
1 as blood flows through the
lungs the haemoglobin in the
red cells picks up oxygen
2 Haemoglobin and
oxygen join to make
oxyhaemoglobin
3 when the blood flows past
cells with very little oxygen
in them the oxyhaemoglobin
breaks down
oxygen diffuses into the cells of the body
oxygen is used for respiration
4 the haemoglobin in the
red cells goes back to
the lungs to pick up
more oxygen
26. DOUBLE CIRCULATION
LUNGS
Left Atrium
Left Ventricle
Body
Right Ventricle
Right Atrium
Pulmonary Circulation
HeartLungsHeart
Systemic Circulation
HeartBodyHeart
Low pressure circulation
Walls of the right ventricle
are thinner and less
muscular than left ventricle
High pressure circulation
Blood has to be pumped to
the furthest part of the body
29. THE HUMAN HEART
The human heart has four chambers – two smaller chambers
(atria) and two large chambers (ventricles)
A muscular wall down the middle SEPTUM, divides the
heart into right half and left half to prevent mixing of
oxygenated and deoxygenated blood
30. The Heart
These are arteries. They
carry blood away from
the heart.
This is a vein. It brings
blood from the body,
except the lungs.
Coronary
arteries, the hearts
own blood supply
The heart has four chambers
2 atria
2 ventricles
31. The Heart
Left Ventricle
Left Atrium
Right Atrium
Right Ventricle
valve
Vein from Lungs
Artery to Head and BodyArtery to Lungs
Vein from Head and Body
valve
32. How does the Heart work?
blood from the
body
blood from
the lungs
The heart beat begins when the
heart muscles relax and blood
flows into the atria.
STEP ONE
33. The atria then contract and
the valves open to allow blood
into the ventricles.
How does the Heart work?
STEP TWO
34. How does the Heart work?
The valves close to stop blood
flowing backwards.
The ventricles contract forcing
the blood to leave the heart.
At the same time, the atria are
relaxing and once again filling with
blood.
The cycle then repeats itself.
STEP THREE
35. SUMMARY
Chambers of the heart, made up of cardiac muscles, contract in pairs
Deoxygenated blood
from two anterior vena
cavae and a posterior
vena cava
Right atrium
Right ventricle
Blood travels through
the pulmonary artery
to the lungs
enters
Oxygenated blood from
the pulmonary vein
arising from the lungs
Left atrium
Left ventricle
Blood travels through the
aorta to be distributed to
other parts of body
enters
Remember:
Happen simultaneously
43. Hypertension (High blood pressure)
Arteriosclerosis (hardening of arteries)
Artherosclerosis (narrowing of arteries)
EXAMPLES
44. Occurs when coronary arteries become clogged less blood
flows through and parts of heart muscles do not get sufficient
blood
Fatty deposits on the walls of the arteries make them narrow
Atherosclerosis progresses gradually
Coronary artery becomes more and more clogged and may
eventually get blocked
CORONARY HEART DISEASE
45.
46. In coronary occlusion, the blood flow in the artery stops and so
does the supply of oxygen and nutrients
CORONARY OCCLUSION
HEART ATTACK WHEN ONE OR MORE
CORONARY ARTERIES BECOME
BLOCKED
51. Reduce consumption of items rich in fats and cholesterol
Eat more heart-healthy food
Stay within ideal weight range by eating right diet
Exercise regularly
Don’t smoke
Reduce stress
PREVENTION
53. WHAT IS BLOOD MADE UP OF?
Red blood cells
White blood cells
Platelets
Plasma
Breakdown products of digestion, such as
glucose, fatty acids and amino acids
Dissolved mineral salts
Carbon dioxide
Urea
hormones
55. WHAT IS PLASMA?
Plasma is the liquid part of the blood which carries everything
else.
Plasma is a straw-yellow coloured liquid
If everything in plasma was removed, plasma would look like
this
57. WHAT DO THE DIFFERENT PARTS
OF BLOOD LOOK LIKE UNDER A
MICROSCOPE?
Red
blood
cells
White
blood
cells
58. WHAT IS THE JOB OF RED BLOOD
CELLS?
They have a round, flat disc
shape for a large surface
area
They do not have a nucleus
They contain haemoglobin
which combines with oxygen
in areas of high
concentration to form
oxyhaemoglobin
Oxygen + haemoglobin
oxyhaemoglobin
Red blood cells carry oxygen
to the cells of the body for
use in respiration
59. WHAT DO WHITE BLOOD CELLS DO?
White blood cells
help the body to
fight invading
bacteria
White blood cells
will engulf and
ingest invading
bacteria
60. OTHER IMPORTANT JOBS OF THE
WHITE BLOOD CELLS:
They produce
antibodies which
can recognise and
fight bacteria
They produce
antitoxins which
neutralise the
toxins (poisons)
that bacteria
produce, which
make us feel ill
61. WHAT DO PLATELETS DO?
Platelets are fragments of cells
The job of platelets is to help blood clot and form a scab
The platelets are involved in the formation of fibrin, which is
needed for clotting blood
This is useful for stopping bleeding, and for preventing germs
from entering the body through the cut